Plain-language answer: RTTY sends text by shifting between two tones or RF frequencies, traditionally called mark and space.
Why operators care
It is robust and widely supported but often has a high transmit duty cycle, so clean audio, correct polarity, and conservative power protect the signal and equipment.
How to use it well
Use the expected shift and baud rate, keep AFSK audio below clipping, disable compression, and watch transmitter temperature.
The common mistake
Running the same indicated peak power used for intermittent voice without checking continuous-duty limits.
Operating boundary
Predictions, reports, schedules, and mode descriptions guide a decision; they do not override current regulations, equipment limits, exact station conditions, or what the operator verifies on air.
